Scientists are beginning to understand how people tune in to a single voice in a crowded, noisy room.
This ability, known as the “cocktail party effect,” appears to rely on areas of the brain that have completely filtered out unwanted sounds, researchers report in the journal Neuron. So when a person decides to focus on a particular speaker, other speakers “have no representation in those [brain] areas,” says Elana Zion Golumbic of Columbia University.
The ability to extract sense from auditory chaos has puzzled scientists since the 1950s, Golumbic says. “It’s something we do all the time, not only in cocktail parties,” she says. “You’re on the street, you’re in a restaurant, you’re in your office. There are a lot of background sounds all the time, and you constantly need to filter them out and focus on the one thing that’s important to you.”
But until a few years ago, how the brain did this was a mystery. That’s changing, Golumbic says, thanks to new technology that allows scientists to monitor many different areas of the brain as they listen to multiple voices.
A better understanding of the cocktail party effect could eventually help people who have trouble deciphering a single voice in a noisy environment, says Edward Chang, an assistant professor of neurological surgery and physiology at the University of California, San Francisco.
That’s a problem for many people as they get older, he says. It’s also a problem for people with attention deficit hyperactivity disorder, or ADHD, Chang says, adding that he saw this problem up close when a person with the disorder volunteered for an experiment that involved trying to focus on just one of two speakers.
“This person had significant problems with the ability to select the correct speaker,” Chang says.
Understanding precisely how the brain solves the cocktail party problem could also allow machines to do a better job deciphering human speech, Chang says. That could mean better cellphones and less frustrating conversations with the computers that often answer phone calls to customer service hotlines.